This proposal addresses a gap in knowledge about the development of Conduct Disorder (CD) and its relationship to precursor, comorbid and subsequent conditions, such as Oppositional Defiant Disorder (ODD), Attention Deficit Hyperactivity (ADHD), -Depression, and Anxiety Disorder. In 1987-88, a sample was formed at two sites, of 177 prepubertal outpatient boys, most of whom had been referred for conduct problems and/or attention deficit-hyperactivity. These boys have now completed the third of four planned annual assessments. In Phase II of the research, this proposal aims to follow up the boys well into adolescence with an additional three annual assessments. The proposed study aims at elucidating the interaction between CD and its comorbid conditions, and relating the persistence and worsening of CD to the presence of other risk factors, such as antisocial personality in parents, poor parenting, deviant peer influences, the boys' intelligence and academic performance. Hypotheses concerning developmental precursors of later onset CD will also be tested, particularly Gittelman et al.'s (1985) assertion that uncomplicated ADHD is a significant precursor to late-onset CD and substance abuse. We propose to take advantage of the unusual opportunity to continue pilot testing over time the apparently robust association of low salivary cortisol and severe CD, identified during Year 2, and to assess salivary testosterone annually primarily as an index of puberty. The study will also allow for an evaluation of the long-term predictive utility of different symptoms and diagnostic criteria (DSM-III-R and possible alternatives) for the classification of disruptive behavior disorders in childhood and adolescence.